U.S. patent number 7,634,217 [Application Number 11/680,005] was granted by the patent office on 2009-12-15 for electrophotographic image forming method using a double walled toner cartridge.
This patent grant is currently assigned to Konica Minolta Business Technologies, Inc.. Invention is credited to Sayuri Nakano, Ken Ohmura, Tomomi Oshiba, Kishio Tamura.
United States Patent |
7,634,217 |
Tamura , et al. |
December 15, 2009 |
Electrophotographic image forming method using a double walled
toner cartridge
Abstract
An image forming method wherein a storage container,
accommodating the toner having a volume-based median diameter of
3.5 .mu.m through 8.5 .mu.m and containing a resin having a
glass-transition temperature of 0.degree. C. through 46.degree. C.
and a softening point of 75.degree. C. through 110.degree. C., is
included in an packaging container made of a substance having an
apparent density of 0.1 through 0.3; and a toner supply section
constituting the storage container is exposed to the outside from
the packaging container, and is loaded on the image forming
apparatus, whereby toner is supplied to the image forming
apparatus.
Inventors: |
Tamura; Kishio (Tokyo,
JP), Ohmura; Ken (Tokyo, JP), Oshiba;
Tomomi (Tokyo, JP), Nakano; Sayuri (Tokyo,
JP) |
Assignee: |
Konica Minolta Business
Technologies, Inc. (Tokyo, JP)
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Family
ID: |
38749661 |
Appl.
No.: |
11/680,005 |
Filed: |
February 28, 2007 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20070274743 A1 |
Nov 29, 2007 |
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Foreign Application Priority Data
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May 4, 2006 [JP] |
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2006-143695 |
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Current U.S.
Class: |
399/258 |
Current CPC
Class: |
G03G
15/0855 (20130101); G03G 15/0879 (20130101); G03G
15/0865 (20130101); G03G 15/0874 (20130101); G03G
2215/068 (20130101); G03G 2215/0682 (20130101) |
Current International
Class: |
G03G
15/08 (20060101) |
Field of
Search: |
;399/258,260,262 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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61138970 |
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Jun 1986 |
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JP |
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05341647 |
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Dec 1993 |
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JP |
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2000060313 |
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Feb 2000 |
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JP |
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2001066831 |
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Mar 2001 |
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JP |
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Primary Examiner: Grainger; Quana M
Attorney, Agent or Firm: Lucas & Mercanti, LLP
Claims
What is claimed is:
1. An image forming method using an electrophotographic method
utilizing toner, comprising steps of: mounting a toner cartridge
having a packaging container and a storage container storing the
toner, on an image forming apparatus, wherein the toner is supplied
through a toner supply section of the storage container to a toner
replenishment section of the image forming apparatus and the
storage container is accommodated in the packaging container, and
the packaging container is formed of a member having a hollow
structure with an apparent density of 0.1 through 0.3; and forming
an image through the electrophotographic process utilizing the
toner from the toner cartridge which is mounted on the image
forming apparatus, wherein the toner contains a resin having a
glass-transition temperature of 0.degree. C. through 46.degree. C.
and a softening point of 75.degree. C. through 110.degree. C., and
having a volume-based median diameter (D50) of 3.5 .mu.m through
8.5 .mu.m, supplied from the storage container.
2. The image forming method of claim 1, wherein the packaging
container and storage container are formed by a material having
transparency that allows an amount of remaining toner to be
identified from outside.
3. The image forming method of claim 2, wherein the storing
container is formed of a flexible bag.
4. The image forming method of claim 3, wherein the packaging
container has a window having transparency that allows an amount of
remaining toner to be identified from outside.
5. The image forming method of claim 4, wherein the packaging
container is formed by a corrugated plastic board having
transparency that allows an amount of remaining toner to be
identified from outside.
6. The image forming method of claim 1, wherein the packaging
container has a window having transparency that allows an amount of
remaining toner to be identified from outside.
7. The image forming method of claim 1, wherein the packaging
container is formed by a corrugated plastic board having
transparency that allows an amount of remaining toner to be
identified from outside.
8. The image forming method of claim 1, wherein the storing
container is formed of a flexible bag.
9. An image forming apparatus using an electrophotographic process
utilizing toner, comprising: a toner cartridge having a storage
container and a packaging container, the storage container storing
toner that contains a resin having a glass transition temperature
of 0.degree. C. through 46.degree. C. and a softening point of
75.degree. C. through 110.degree. C., and having a volume-based
median diameter (D50) of 3.5 .mu.m through 8.5 .mu.m; the packaging
container formed by a member having a hollow structure with an
apparent density of 0.1 through 0.3 to accommodate the storage
container; and a toner supply section to supply the toner to the
image forming apparatus by exposing the toner supply section
through an opening provided on the packaging container; wherein the
toner cartridge is mounted on the image forming apparatus in such a
state that the storage section is accommodated in the packaging
container during the electrophotographic process of the image
forming apparatus while supplying toner to the image forming
apparatus.
10. The image forming apparatus of claim 9, wherein the storing
container is formed of a flexible bag.
11. The image forming apparatus of claim 10, wherein the packaging
container and the storage container are formed by a material having
transparency that allows an amount of remaining toner to be
identified from outside.
12. The image forming apparatus of claim 11, wherein the packaging
container has a window having transparency that allows an amount of
remaining toner to be identified from outside.
13. The image forming apparatus of claim 12, wherein the packaging
container is formed by a corrugated plastic board having
transparency that allows an amount of remaining toner to be
identified from outside.
14. The image forming apparatus of claim 9, wherein the packaging
container and the storage container are formed by a material having
transparency that allows an amount of remaining toner to be
identified from outside.
15. The image forming apparatus of claim 9, wherein the packaging
container has a window having transparency that allows an amount of
remaining toner to be identified from outside.
16. The image forming apparatus of claim 15, wherein the packaging
container is formed by a corrugated plastic board having
transparency that allows an amount of remaining toner to be
identified from outside.
17. The image forming method of claim 1, further comprising a step
of exposing the toner supply section of the storage container
through an opening section provided on the packaging container to
supply the toner.
Description
CROSS-REFERENCE TO RELATED APPLICATION
The present application is based on Japanese Patent Application No.
2006-143695 filed with Japan Patent Office on May 24, 2006, entire
content of which is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
The present invention relates to an image forming method wherein
toner is supplied to an image forming apparatus from a toner
cartridge made up of a toner storage container and a packaging
container for packaging a storage container.
In the field of image forming technique using an
electrophotographic process in recent years, studies have been made
to develop a technique for forming an image with less power
consumption to give consideration to global environment. One of
such techniques has succeeded in forming an image at a fixing
temperature lower than the conventional temperature by utilizing a
polymerized toner or the like containing the wax of lower melting
point (e.g., Patent Document 1).
When storing such toner especially in a high-temperature
environment, there is a concern about a problem of blocking wherein
toner particles are coagulated with one another by heat. To
eliminate the possibility of causing blocking during toner storage,
development efforts have been made to find out a method of
accommodating and storing toner in a container characterized by
excellent heat insulation.
The following describes the techniques on a toner container of
excellent heat insulation. One of such techniques is exemplified by
the invention wherein a toner container uses an organic expandable
material as either the inner shell material and outer shell
material of a thin-walled synthetic resin-made supporting member or
the intermediate material of two supporting members having
two-layer structure (e.g., Patent Document 2). Another example is
an invention of using a toner container formed of a material having
heat conductivity below a predetermined value (e.g., Patent
Document 3). A further example is provided an invention wherein a
plurality of plastic molded products forming the heat insulating
layer are employed to produce a toner container that maintains high
printing accuracy in a high-temperature environment (e.g., Patent
Document 4). As described above, efforts have been made to develop
the techniques for maintaining the toner quality without being
affected by the environment, and achieving stable preservation.
[Patent Document 1] Unexamined Japanese Patent Application
Publication No. 2001-42564
[Patent Document 2] Unexamined Japanese Patent Application
Publication No. H5-341647
[Patent Document 3] Unexamined Japanese Patent Application
Publication No. H6-72472
[Patent Document 4] Unexamined Japanese Patent Application
Publication No. 2004-13085
The main stream in the image forming apparatus based on
electrophotographic technology has been the technique wherein a
toner-containing cartridge is mounted on an apparatus and toner is
supplied from the mounted cartridge. The containers disclosed in
the aforementioned Patent Documents 2 and 3 are intended to store
and convey toner, but these documents fail to describe use of the
container itself as a cartridge being mounted on the main body of
the image forming apparatus. Further, the Patent Document 4
discloses a toner container used as a cartridge. In this technique,
however, much time and effort have been required to manufacture a
cartridge. For example, in order to form a resin layer constituting
the cartridge and a heat insulating layer, a great number of
molding operations has to be performed to form a sandwich
structure.
SUMMARY OF THE INVENTION
An object of the present invention is to provide an image forming
method that can ensure stable image formation with toner
characterized by low-temperature fixing property, by using a toner
cartridge that can be manufactured in a simple process and can be
stored and conveyed without the stored toner being affected by
fluctuation of outside air.
Another object of the present invention is to provide an
environment-friendly and user-friendly image forming method by
using a toner cartridge capable of ensuring that the burden
resulting from generation of waste or utilization is not imposed on
a user.
One aspect of the invention can be an image forming method wherein
toner is supplied to an image forming apparatus loaded on a storage
container for storing the toner that contains a resin having a
glass-transition temperature of 0.degree. C. through 46.degree. C.
and a softening point of 75.degree. C. through 110.degree. C., and
having a volume-based median diameter (D50) of 3.5 .mu.m through
8.5 .mu.m; wherein this storage container is included in an
packaging container made of a substance with an apparent density of
0.1 through 0.3, and is loaded on the image forming apparatus to
supply toner, after a toner supply section constituting the storage
container is exposed from the packaging container.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic perspective view of an example of a toner
cartridge of the present invention.
FIG. 2 is a schematic perspective view of a storage container 200
for storing toner.
FIG. 3 is a schematic perspective view showing another embodiment
of the storage container 200 for storing toner.
FIG. 4 is a schematic perspective view of a packaging container 300
for storing toner.
FIG. 5 is a schematic view representing the cross sectional
structure of a material that can be used in the packaging container
300.
FIG. 6 is a schematic view for manufacturing an apparent density
measuring material piece from the packaging container 300.
FIG. 7 is a cross sectional view of the toner replenishment section
in the mage forming apparatus in FIG. 9 as observed along the line
Z-Z.
FIG. 8 is a schematic perspective view of the nozzle member 200B
broken away for illustration;
FIG. 9 is a side view and partial plan view in the vicinity of the
toner replenishment section 100.
FIG. 10 is a schematic perspective view representing another
embodiment of the toner cartridge of the present invention.
FIG. 11 is a schematic diagram representing tandem type color image
forming apparatus.
FIG. 12 is a schematic diagram representing the internal structure
of a development apparatus 4 and a toner replenishment section.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The objects of the present invention can be achieved by utilizing a
toner cartridge wherein a storage container storing toner having
low-temperature fixing property is packaged in a packaging
container made of a substance having a specific gravity within a
predetermined range. To be more specific, the material having an
apparent density within a predetermined range is selected as a
material of packaging container to ensure that the toner stored in
the storage container is not affected by outside air. When
four-color toner products have been set especially at the time of
color image forming, a subtle temperature difference occurs
depending on the set position of each toner cartridge. Further, the
influence of the fluctuation in humidity will take effect. Thus,
there is a concern that a difference in the amount of static charge
will occur among toner products of various colors. In the present
invention, the cartridge including the packaging container is
mounted on the image forming apparatus, thereby avoiding these
problems and ensuring stable color reproduction.
As described above, the present invention improves toner storage
stability by using a toner cartridge, a toner storage container and
a storage container packaging container, and by giving a superb
heat insulation property to the packaging container originally
intended for impact absorption.
The following describes the details of embodiments related to the
present invention:
In the first place, the following describes an example of
embodiment of a representative toner cartridge applicable to the
present invention, with reference to drawings. The toner cartridge
in the sense in which it is used in the present invention refers to
a toner container that includes toner and is directly mounted on
the main body of the image forming apparatus to supply toner.
The assertive expression in the following description of the
embodiment is based on the best mode without restricting the
meaning or technological scope of the terminology used in the
present invention.
The toner cartridge 50 of FIG. 1 includes a toner storage container
200 and a packaging container 300 for packaging the storage
container 200. The packaging container 300 also functions as a
packaging material. It absorbs impact during the conveyance and
reinforces the storage container 200 incorporated therein. The
packaging container 300 is formed of a substance having an apparent
density of 0.1 through 0.3. When impact is applied to the toner
cartridge, the packaging container 300 absorbs the impact. During
storage or conveyance in the high-temperature environment, the
excellent heat insulation property of the packaging container 300
blocks heat so that it will not be transferred to the toner
contained in the storage container 200. As described above, the
packaging container 300 protects the storage container 200 and the
toner incorporated in the storage container 200.
Further, on the market, the information used during the time from
the shipment from the factory of the unitary package box to the
arrival at the final user, and the information used when collecting
the used cartridge are printed, for example, on the labels which
can be bonded on the packaging container 300. The packaging
container 300 is called a unitary package box, package box or
packaging container on the market.
Referring to FIG. 1 through FIG. 3, the following describes the
toner cartridge 50.
FIG. 1 is a schematic perspective view of a toner cartridge 50. Of
the side surfaces forming a packaging container 300, the opening
300A that can be opened or closed is opened in such a way that the
nozzle member 200B is exposed to the outside, wherein this nozzle
member 200B corresponds to the supply section for supplying the
image forming apparatus with the toner stored in the storage
container 200. In the conventional art, when the toner cartridge 50
is to be mounted on the image forming apparatus, only the storage
container 200 is mounted on the image forming apparatus. There has
been no case where the storage container is mounted together with
the packaging container 300. In the present invention, when the
toner cartridge 50 is to be mounted on the image forming apparatus,
the storage container 200 packaged in the packaging container 300
is mounted on the image forming apparatus. This arrangement solves
the problem of requiring much time and efforts in storing the
packaging container 300 during supply of toner.
Although not illustrated, a detection piece (fool proof) and IC
chip can be attached to the toner cartridge 50.
Further, as shown in FIG. 1, the toner cartridge 50 allows the
packaging container 300 to be provided with small windows 305A and
305B for checking the amount of remaining toner inside the storage
container 200.
FIG. 2 is a schematic perspective view of a storage container 200.
FIG. 3 is a schematic perspective view showing another embodiment
of the storage container 200.
As shown in FIG. 2, the storage container 200 contains a flexible
bag 200A such as polyethylene and nylon for storing toner, and a
nozzle member 200B representing the supply section for charging and
discharging toner.
As illustrated, the bag 200A contains a funnel section 200C for
smooth ejection of toner. The narrower leading end 200D of the
funnel section 200C is bonded and secured in the sealed state so as
to enclose the nozzle member 200B.
As described, for example, in the Unexamined Japanese Patent
Application Publication No. 2005-309168, the bag 200A can be
manufactured as a plurality of sheet members constituting each side
surface are bonded with each other.
The details of the nozzle member 200B are described later.
FIG. 3 is a schematic perspective view showing another embodiment
of the storage container 200. This storage container 200 is made up
of a bag 200E for storing the toner manufactured by blow molding or
the like, and a nozzle member 200F for charging and discharging
toner.
As shown in FIG. 3, the bag 200E has a funnel section 200G, and the
narrower leading end 200H of the funnel section 200G is secured on
the nozzle member 200F by bonding in a sealed state.
The nozzle member 200F has the same basic structure as that of the
aforementioned nozzle member 200B.
A filter member 200J is secured on the bottom surface of the bag
200E by bonding. This arrangement is intended to ensure that, when
toner is sucked by a powder pump (to be described later), the
filter supplies air but not toner so that the interior of the bag
200E will not be exposed to excessive negative pressure.
Use of the storage container having a flexible bag, for example,
eliminates the need of using a cushioning material, and provides a
simple and compact cartridge structure. When the used cartridge is
collected, a greater number of used cartridges can be loaded on a
truck. Such advantages can be expected.
With reference to FIG. 4, the following describes the packaging
container 300 for packaging the toner storage container 200. The
packaging container 300 can be used at the time of transportation.
It is strong enough to withstand the impact imposed at the time of
transportation, and is weather-resistant so that printing on the
container surface will not be adversely affected by rain.
The surface of the packaging container 300 can be printed with the
product name, caution signal and check mark at the time of
transportation.
Further, the packaging container 300 is manufactured by the
material having an apparent density of 0.1 through 0.3. Use of the
material having the apparent density within the aforementioned
range ensures that the packaging container 300 is provided with
heat insulation property as well as the aforementioned impact
absorbency and weatherability. As a result, the toner that could
not withstand a long-term storage and conveyance in the
high-temperature environment, such as the toner having a
low-temperature fixing property, can now be stored and conveyed
under stable conditions without being affected by the fluctuation
of outside air.
The material having the apparent density within the aforementioned
range can be obtained by using, for example, paper such as a
corrugated board and molded pulp material, resin material such as
expandable polystyrene resin and polyester resin, a
double-structured bag made of paper and resin, or a combination of
these. The surface of these materials can be processed to permit
transportation-related information to be printed.
The material that can be used in the packaging container 300 can be
exemplified by a plastic-made corrugated board, paper-made
corrugated fiberboard, expandable polyethylene, expandable
polystyrene and expandable rubber. The packaging container 300
having density of 0.1 through 0.3 is manufactured by forming a
cross sectional structure shown in FIG. 5 using these
materials.
Of these materials, the plastic-made corrugated board provides a
certain degree of transparency. This provides an advantage of
checking the amount of remaining toner. Even when the packaging
container 300 is manufactured using the material other than the
plastic-made corrugated fiberboard, the windows 305A and 305B are
provided, using a polyethylene terephthalate (PET) sheet and
cellophane sheet, as shown in FIG. 1. This makes it possible to
check the amount of toner remaining in the storage container.
As described above, the toner cartridge is provided with a small
window to check the amount of remaining toner in the toner
cartridge being used. This arrangement eliminates the need of the
user stocking more than a necessary number of toner cartridges.
This provides an advantage of avoiding excess inventory of
cartridges. Especially when storing the toner for low-temperature
fixing, the user cannot provide the same temperature control as
that at the manufacturer or dealer for the storage of toner.
However, the user can predict a correct time of ordering a new
toner cartridge by checking the amount of remaining toner through
the small window. This arrangement facilitates the stock control of
the toner cartridge on the part of the user, and eliminates the
possibility that the toner having been coagulated by heat is used
for image forming.
An apparent density of the material applicable to the packaging
container 300 can be measured according to the following procedure,
for example: FIG. 6 outlines the procedure of manufacturing a
material piece for measuring the apparent density using the
packaging container 300. (1) Use a cutter to cut out a material
piece from the packaging container 300. The size of the material
piece can be as desired, but the material piece should be cut out
from the portion which is not in contact with the collected
material, wherever possible. (2) Cut this material piece to a
predetermined size and get a rectangle having a length of "a" cm
and width of "b" cm, as shown in FIG. 6. Also measure the thickness
(t) of the material piece. (3) The material piece having been
trimmed is placed on a chemical balance and the mass is measured.
(4) The mass having been measured is divided by the volume of the
material piece, and the resulting value is assumed as the apparent
density. (5) For example, the packaging container 300 of FIG. 6 has
a thickness of "t" cm, and a material piece having a length of "a"
cm and width of "b" cm, is prepared. When the mass of this material
piece is m (g), the apparent density of the material constituting
the packaging container 300 is expressed by the following formula:
Apparent density (density
(g/cm.sup.3))=m(g)/(a(cm).times.b(cm).times.t(cm))
The following methods can be used to ensure that the apparent
density of the material constituting the packaging container 300 is
0.1 through 0.3. In one of these methods, when forming a material
by assembling a sheet of paper or plate-formed plastic as in the
case of a corrugated board, arrangements are made so that a space
is formed between members. According to another method, when
molding is performed in a die to produce the material as in the
case of an expandable material, expansion molding is performed to
form fine air bubbles in resin. Such methods can be mentioned as
examples. When producing these materials, the space ratio, the
amount of air supplied at the time of expansion molding are
obtained by calculation in advance, and the material is designed,
based on this calculation result. This procedure produces the
material for packaging container having the aforementioned apparent
density.
FIG. 5 shows the cross sectional structure of a material that can
be used in the packaging container 300. The (a) through (c) of FIG.
5 indicate the materials having been assembled to form a space
between the members such as a corrugated fiberboard. The (d)
through (f) of FIG. 5 show the materials containing fine air
bubbles in resin.
The material shown in FIG. 5(a) through FIG. 5(c) is typically
represented by a corrugated fiberboard made of a medium. The
corrugated fiberboard specified in the JIS Z 0108 has a structure
wherein a flat medium called a liner is bonded on one or both sides
of the corrugating medium (called corrugate). FIG. 5(a) shows what
is called a two-sided corrugated fiberboard, wherein liners are
bonded on both sides of the corrugated medium. FIG. 5(b) represents
what is called a double wall double faced corrugated fiberboard,
wherein a single faced corrugated fiberboard (corrugating medium
bonded on one liner) is bonded on one side of the double faced
corrugated fiberboard. FIG. 5(c) shows what is called a triple wall
corrugated fiberboard wherein a single face corrugated fiberboard
is bonded on one side of the double wall double faced corrugated
fiberboard.
A plastic material such as polypropylene, polystyrene, polyethylene
terephthalate (PET), acrylonitrile-styrene-butadiene copolymer
(ABS) and polyethylene can be preferably used instead of the
medium. When these resin materials are used, molding is performed
so that the product will be transparent or translucent throughout
the entire body.
FIGS. 5(d) through FIG. 5(f) show what is called a foaming material
containing fine air bubbles. It is produced by mixing the foaming
member with the resin material at the time of injection molding.
The specific example of the foaming member includes a gas such as
methane, butane, carbon dioxide gas, nitrogen and argon gas. An
organic substance such as a piece of paper, a piece of wood and a
bamboo fiber can be used as a foaming member. The organic substance
such as a piece of paper, a piece of wood and a bamboo fiber are
made up of very fine fibrous materials and contains very fine air
bubbles.
FIG. 5(d) shows the structure wherein round air bubbles are
dispersed in the resin phase. FIG. 5(e) shows the structure wherein
an organic substance such as a piece of paper, a piece of wood and
a bamboo fiber is dispersed in the resin phase. FIG. 5(f) shows a
three-layered structure wherein a layer containing air bubbles is
arranged between two resin layers.
When the packaging container 300 is manufactured using the material
having the apparent density within the aforementioned range, the
packaging container 300 is provided with heat insulation property.
The toner storage container 200 packaged in the packaging container
300 can be stored and conveyed almost without being affected by the
external environment. To be more specific, the heat of the toner
cartridge external is transmitted over the surface of the packaging
container 300, but there is a great decrease in the speed of heat
transfer through the space in the corrugated fiberboard or the air
bubble provided in the resin. Since there is a great decrease in
the speed of heat transfer through the space in the packaging
container 300 as described above, there is almost no transfer of
external heat inside the packaging container 300 in contact with
the toner storage container 200. Thus, toner storage container 200
is preserved without being affected by the fluctuation of outside
air.
Referring to FIG. 4, the following further describes the packaging
container 300. In the packaging container 300, the side surface
opposite to the nozzle member 200B of the toner storage container
200 accommodating the toner storage container 200 is made up of a
front flap 301, rear flap 302, left flap 303 and right flap
304.
The reference numeral 301A denotes a fitting holding hole arranged
almost at the center of the front flap 301. As shown in FIG. 1, the
diameter of the nozzle holding hole 301A is almost the same as that
of the nozzle member 200B of the storage container 200. It performs
the function of ensuring that the nozzle member 200B does not move
when the storage container 200 is accommodated.
The reference numeral 301B denotes a tongue arranged on the leading
end of the front flap 301. As shown in FIG. 1, it accommodates the
storage container 200. When the front flap 301 is folded inside,
the tongue 301B is engaged with the slit 301C arranged on the
packaging container 300.
Since the tongue 301B is engaged with the slit 301C as described
above, storage container 200 is prevented from jumping out
downward, through collaboration with the nozzle holding hole 301A,
when the nozzle member 200B of the storage container 200 is cast
down for the purpose of supplying supply.
In addition to the aforementioned method, the storage container 200
can be fastened on the packaging container 300 by bonding the bag
200A of the storage container 200 on the packaging container 300
using a double-faced tape. For example, one surface of the bag 200A
can be secured on the inner surface of the packaging container 300
by a double-faced tape T.
Once the bag 200A is fastened in position as described above, bag
200A shrinks evenly when toner is sucked from the storage container
200. This arrangement prevents the part of the bag 200A being bent,
and toner from remaining therein.
Uniform shrinkage of the bag 200A eliminates the need of bonding a
reinforcing member such as a PET (polyethylene terephthalate) sheet
on the surface, for example. This contributes to a further
reduction in the weight of the bag 200, as well as further saving
of resources and costs.
The leading ends of the rear flap 302, left flap 303 and right flap
304 are provided with the tongues 302A, 303A and 304A,
respectively.
The tongues 302A, 303A and 304A are engaged with the slits 302B,
303B and 304B provided on the packaging container 300 corresponding
respectively, when toner is supplied.
The aforementioned engagement of the tongues 302A, 303A and 304A
with the slits 302B, 303B and 304B ensures accurate and smooth
mounting (or dismounting) of the packaging container 300 on the
toner replenishment section 100 (FIG. 7 and FIG. 8).
A self-adhesive tape may be used to secure the tongues 302A, 303A
and 304A on the side surface of the packaging container 300.
The following describes the procedure of forming the side surface
opposite to the nozzle member 200B of the storage container 200 of
the aforementioned packaging container 300.
The storage container 200 charged with toner is inserted in the
packaging container 300, and the nozzle member 200B is inserted
into the fitting holding hole 301A of the front flap 301. Then
after being bent at the polygonal line portion 301D, the tongues
301B is engaged with the slit 301C from below.
After that, the left flap 303 and right flap 304 are folded inside,
and the insertion part 302C of the rear flap 302 is inserted into
the packaging container 300 in the final step.
Referring to FIGS. 7 and 8, the following describes the details of
the nozzle member 200B corresponding to the supply section of the
storage container 200.
FIG. 7 is a cross sectional view of the toner replenishment section
100 in the tandem type color image forming apparatus of FIG. 11 as
observed along the line Z-Z. The nozzle member 200B of the storage
container 200 is fitted and mounted on the toner replenishment
section 100.
FIG. 8 is a schematic exploded perspective view of the nozzle
member 200B. The nozzle member 200B is provided with a first nozzle
member 210 and second nozzle member 230.
The second nozzle member 230 is provided with two locking portions
231. The locking portions 231 enters a concaved receiving section
211 arranged on the first nozzle member 210, and the claw 232 of
the locking portions 231 is engaged with a jaw 212 of the first
nozzle member 210. Then the first nozzle member 210 and the second
nozzle member 230 are fastened at predetermined relative
positions.
The first and second nozzle member 210 and 230 being fastened can
be separated by pulling the second nozzle member 230 in the
downward direction of FIG. 8.
A first toner outlet 215 made up of a tapered portion 213 wider
toward the top in FIG. 8 and a cylindrical section 214 connected
thereto is provided at the center of the first nozzle member 210.
The first toner outlet 215 communicates with the second toner
outlet 233 arranged on the second nozzle member 230.
The open/close member 250 arranged on the side of the image forming
apparatus is slidable in a hole 234 arranged to cross the second
toner outlet 233. The part thereof is provided with a cylindrical
toner passage section 251 having a diameter smaller than that of
the cylindrical section.
Referring to FIG. 7, FIG. 8, the following describes the details of
the toner replenishment section 100 of the main body of the image
forming apparatus (FIG. 11).
In FIG. 7, the reference numeral 101 denotes a toner receiving
member to receive the toner storage container 200 and packaging
container 300 which are to be fitted and mounted on the toner
replenishment section 100. A tapered portion 102 matching with the
tapered portion of the leading end of the second nozzle member 230
is formed approximately at the center.
The reference numeral 103 is a third toner outlet provided at the
center of the toner receiving member 101. This toner outlet
communicates the second toner outlet 233 of the second nozzle
member 230 through the tapered portion 102. At the bottom end, the
toner outlet is connected with the tube 415 connected to the
suction portion of the powder pump (to be described later).
The reference numerals 104 and 105 denote the stoppers for
receiving the packaging container 300. They are arranged in such a
way that, when the tapered portion of the leading end of the second
nozzle member 230 matches with the tapered portion 102 of the toner
receiving member 101, the leading end of the packaging container
300 comes in engagement therewith.
The reference numeral 106 refers to a cylindrical pressure member
held movably by the toner receiving member 101 in the lateral
direction (in the horizontal direction) of FIG. 7. The cylindrical
pressure member is arranged at such a position that, when the
nozzle member 200B is loaded on the toner replenishment section
100, the centerline of the pressure member 106 matches with the
centerline of the open/close member 250.
The reference numeral 107 represents a drive pin secured on the
pressure member 106. It is arranged in the direction perpendicular
to the centerline of the pressure member 106 (in the direction
vertical to the sheet surface of FIG. 7).
As shown in FIG. 8, the reference numerals 108 and 109 are the
rectangular positioning members fastened to the drive pin 107 on
both sides of the pressure member 106, and are held movably by the
toner receiving member 101 in the lateral direction (in the
horizontal direction) of FIG. 8. The positioning members are
located in such a way as to enter the concave positioning sections
235 and 236 of the second nozzle member 230 when the nozzle member
200B is loaded on the toner replenishment section 100.
The reference numeral 110 represents a drive lever which is
provided so as to be rocked about a fulcrum 111 arranged on the
toner receiving member 101. It has a slot portion 112, and the
drive pin 107 is movably engaged with the slot portion 112.
As shown in FIG. 7, the reference numeral 113 indicates a drive
lever pressure member fastened on the door 114. When the door 114
is closed, the leading end of the drive lever pressure member 113
is held in engagement with the intermediate position between the
slot portion 112 of the drive lever 110 and the fulcrum 111 and is
used to move the pressure member 106 and positioning members 108
and 109 to the left.
After this procedure, the positioning members 108 and 109 enter the
position between the positioning sections 235 and 236 of the second
nozzle member 230 so that the second nozzle member 230 is
accurately fixed in position. At the same time, the pressure member
106 moves the open/close member 250 to the left so that the toner
passage section 251 will be located as shown in FIG. 7, whereby
toner can be supplied.
The reference numeral 115 is a drive lever return spring to return
the drive lever 110 when the door 114 has been opened.
The reference numeral 116 is a cylindrical return member held by
the toner receiving member 101 movably in the lateral direction (in
the horizontal direction) of FIG. 7. The centerline thereof agrees
with that of the open/close member 250.
The reference numeral 117 is a return spring to impose the return
member 116 to move to the right in FIG. 7.
As shown in FIG. 7, when the door 114 is closed, the return member
116 is driven by the open/close member 250 to slide to the left.
When the door 114 is opened, the return member 116 is driven by the
return spring 117 to slide to the right. The open/close member 250
is pushed back until the leading end 250A of the second nozzle
member 230 is aligned with the outer peripheral surface of the
second nozzle member 230. To be more specific, it moves the toner
passage section 251 to the right to interrupt passage of the
toner.
The following describes the operation of each section to be
performed in response to mounting or dismounting of the packaging
container 300 of the aforementioned structure on the toner
replenishment section 100.
Before mounting the packaging container 300 (FIG. 1 and FIG. 4)
incorporating the storage container 200 on the toner replenishment
section 100, the operator inserts members on the side opposite the
nozzle member 200B i.e. the tongues 302A, 303A and 304A of the rear
flap 302, left flap 303 and right flap 304, into the slits 302B,
303B and 304B.
This procedure allows the side opposite to the nozzle member 200B
to be released, as shown in FIG. 1, and causes the opening 300A to
be formed, and the nozzle member 200B to be exposed.
The following describes the procedure of mounting the packaging
container 300 on the toner replenishment section 100, with
reference to FIG. 9(a) and FIG. 9(b).
FIG. 9 is a side view in the vicinity of the toner replenishment
section 100 of FIG. 10. FIG. 9(b) is a partial plan view of FIG.
9(a).
The operator opens the door 114. To mount the packaging container
300 of FIG. 1 accurately at a predetermined position, the operator
inserts it in position along the guide plates 118 arranged at four
positions until the leading end of the packaging container 300
comes in contact with stoppers 104 and 105 (FIG. 7), and the
tapered portion of the second nozzle member 230 comes in contact
with the tapered portion 102 of the toner receiving member 101.
After the operator has completed mounting of the packaging
container 300 and has closed the door 114, the drive lever pressure
member 113 is rocked in the counterclockwise direction of FIG. 7.
This is accompanied by rocking of the drive lever 110 in the
counterclockwise direction about the fulcrum 111.
Rocking of the drive lever 110 causes the positioning members 108
and 109 to be fed forward through the drive pin 107, and to be fed
into the positioning sections 235 and 236 of the second nozzle
member 230. Thus, the second nozzle member 230 is accurately and
tightly fixed in position without being unseated. The pressure
member 106 is also fed forward and the open/close member 250 is fed
to the left so that the toner passage section 251 is located at the
position shown in FIG. 7, whereby toner can be supplied.
The return member 116 is fed backward by the leftward traveling of
the open/close member 250.
Upon completion of the aforementioned procedure, the operator
operates the image forming apparatus. Then the toner contained in
the storage container 200 is supplied into the image forming
apparatus, as will be described later.
If the toner in the storage container 200 has been used up, the
operator opens the door 114 to take out the packaging container
300.
As the door 114 is opened, the return member 116 moves the
open/close member 250 back to a predetermined position in the
second nozzle member 230. At the same time, the drive lever 110 is
rocked about the fulcrum 111 in the clockwise direction through the
action of the drive lever return spring 115.
When the drive lever 110 is rocked, the pressure member 106 and
positioning members 108 and 109 move backward to be disconnected
from the second nozzle member 230, and go back to a predetermined
position.
The operator closes the rear flap 302, left flap 303 and right flap
304 of the packaging container 300 having been taken out, so that
the used cartridge can be collected for recycling. In this way, the
packaging container 300 remains without being removed from storage
container. This arrangement ensures the operator to collect the
used cartridge quickly and easily for reuse.
FIG. 10 is a schematic perspective view representing another
embodiment of the toner cartridge that can be used in the present
invention. In the toner cartridge of FIG. 10, an opening 310 is
arranged below the packaging container 300 so that the toner supply
section 201 of the storage container 200 is exposed to the outside.
Before being mounted on the image forming apparatus, the opening
310 is constructed integrally with the packaging container 300.
When mounted on the image forming apparatus, the opening 310 is cut
off along the perforated line, whereby the toner supply section 201
is exposed to the outside.
The toner supply section 201 is provided with a cock 202 and
fitting portion 204. When exposed to the outside through the
opening 310 of the packaging container 300, the fitting portion 204
is connected to the image forming apparatus and the cock 202 is
opened. Then toner of the storage container 200 is supplied to the
image forming apparatus.
The outer periphery of the packaging container 300 is reinforced by
a band 205 made of resin such as polyethylene. A grip 206 is
provided removably on the upper part of the packaging container 300
through the band 205, thereby improving the workability at the time
of installation on the image forming apparatus. The toner cartridge
can also be secured onto the image forming apparatus through the
grip 206.
Referring to the schematic diagram of a tandem type color image
forming apparatus of FIG. 11, an embodiment of an image forming
apparatus suitable for the aforementioned cartridge is
explained.
The tandem type color image forming apparatus of FIG. 11 includes a
plurality of image forming sections 10Y, 10M, 10C and 10K, an
endless belt-shaped intermediate transfer member unit 7, sheet feed
conveyance device (without reference numeral) and fixing device 24.
A document image reading apparatus B is arranged on the upper
portion of the main body A of the image forming apparatus.
The image forming section 10Y for yellow-colored image forming is
provided with a photoreceptor 1Y as image carrier, a charging
device 2Y around this photoreceptor 1Y, an exposure device 3Y, a
development apparatus 4Y, a primary transfer roller 5Y, a cleaning
device 6Y and others. Other image forming sections 10M, 10C and 10K
are structured in the same way as the image forming section
10Y.
Each of the development apparatuses 4 contains the two-component
developer (or one-component development) made up of toner of each
color charged to have the same polarity as that of each
photoreceptor 1, and contains a development roller as a developer
carrier formed of a cylindrical non-magnetic stainless steel or
aluminum material having a thickness of 0.5 mm through 1 mm and an
outer diameter of 15 mm through 25 mm.
The development roller 41 is held in a contactless state by an
abutting roller (not illustrated) at a predetermined space from the
photoreceptor 1, e.g., at a space of 100 .mu.m through 1000 .mu.m.
It rotates in the same direction as the photoreceptor 1 at a
position opposite the photoreceptor.
At the time of development, the d.c. voltage having the polarity as
that of toner or the development bias voltage obtained by
superimposition of a.c. voltage upon the d.c. voltage is applied to
the development roller 41, thereby causing reverse development in a
state not in contact with the electrostatic latent image on the
photoreceptor 1.
The intermediate transfer member unit 7 includes a plurality of
rollers 71, 72, 73, 74 and 75, and a semiconducting, endless
belt-shaped intermediate transfer member 70 as an image
carrier.
The intermediate transfer member 70 is provided in a form
circumscribing a drive roller 73 connected to a drive motor (not
illustrated), support rollers 71 and 72, secondary transfer backup
roller 74, and backup roller 75 to ensure that the intermediate
transfer member 70 will rotate in the clockwise direction in FIG.
11.
A primary transfer roller 5 for each color is provided opposite the
photoreceptor 1 through the intermediate transfer member 70. The
d.c. voltage having the polarity reverse to that of the toner is
applied to the primary transfer roller 5, and a transfer field is
formed in the transfer area, whereby the toner image of each color
formed on the photoreceptor 1 is primarily transferred onto the
intermediate transfer member 70.
A secondary transfer roller 5A as an image forming device is
arranged opposite the secondary transfer backup roller 74 through
the intermediate transfer member 70. The d.c. voltage having the
polarity reverse to that of toner is applied to the secondary
transfer roller 5A, and a transfer field is formed in the transfer
area, whereby the superimposed toner image carried on the
intermediate transfer member 70 is secondarily transferred onto the
surface of the transfer material (paper) P.
The sheet P is fed from the sheet feed cassette 20 by the sheet
feed device 21, and is conveyed to the secondary transfer position
through a plurality of the intermediate rollers 22A, 22B, 22C and
22D, and registration roller 23, whereby the color images are
collectively transferred.
The sheet P with the color image transferred thereon is subjected
to the process of fixing by the fixing device 24. Being sandwiched
between ejection rollers 25, the sheet P is placed on the ejection
tray 26.
A cleaning unit 60 for removing the toner remaining on the
intermediate transfer member 70 is provided on the downstream side
of the secondary transfer position, as viewed from the rotating
direction of the intermediate transfer member 70.
The details of the development apparatus 4 will be described
later.
The following describes the image forming process with reference to
FIG. 11.
Upon start of the image recording, the drive motor (not
illustrated) of the photoreceptor 1Y starts, and the photoreceptor
1Y of the yellow (Y) image forming section 10Y is driven in the
direction shown by an arrow in FIG. 11 (in the counterclockwise
direction). At the same time, a potential is applied to the
photoreceptor 1Y by the charging by the charging section 2Y.
After potential has been applied to the photoreceptor 1Y, the
exposure device 3Y causes the image writing operation to be
initiated by the first color signal, namely, an electrical signal
corresponding to the Y image data. The electrostatic latent image
corresponding to the Y image of the document image is formed on the
surface of the photoreceptor 1Y.
The aforementioned electrostatic latent image is subjected to
reverse development by the development roller 41 in contact or
contactless state, and a toner image is formed on the photoreceptor
1 in response to the rotation of the photoreceptor 1Y.
The toner image formed on the photoreceptor 1 by the aforementioned
image forming process is transferred onto the intermediate transfer
member 70 by the primary transfer roller 5. Then subsequent to
synchronization with a toner image on the intermediate transfer
member 70, the toner images of magenta (M), cyan (C) and black (K)
are sequentially formed. Thus, a color toner image is formed on the
intermediate transfer member 70.
The toner remaining on the surface of the photoreceptor 1
subsequent to transfer is removed by the cleaning unit 6.
Synchronously with formation of a color toner image on the
intermediate transfer member 70, the sheets P having been conveyed
by being separated one by one from the sheet feed cassette 20 is
fed through the registration roller 23, and color toner images on
the intermediate transfer member 70 are collectively transferred
thereon by the secondary transfer roller 5A.
The sheet P subsequent to transfer is electrically discharged by
the separation unit (not illustrated), and is conveyed to the
fixing apparatus 24. Upon fixing of the toner image, the sheet is
ejected to the ejection tray 26 by the ejection roller 25.
The toner remaining on the surface of the intermediate transfer
member 70 subsequent to transfer is removed by the cleaning unit
60.
The development apparatus 4 includes the development sleeve 401
arranged opposite the photoreceptor 1, first agitating screw 402
and second agitating screw 403, as shown in FIG. 12. In the
development apparatus 4, the developer is conveyed and circulated
by the first agitating screw 402, and, the second agitating screw
403. During this circulation of the developer, the electrostatic
latent image formed on the photoreceptor 1 is developed by the
developer transferred to the development sleeve 401 at some
midpoint of the sheet conveyance path. The reference numeral 4A
denotes a toner density sensor.
A powder pump 404 is mounted on the top of the development
apparatus 4. The toner stored in the storage container 200 of the
toner cartridge 50 is supplied into the development apparatus
4.
The following describes the toner that can be used in the present
invention. In the present invention, it is possible to use the
toner having a volume-based median diameter (D50) of 3.5 .mu.m
through 8.5 .mu.m, wherein the resin contained therein has a
glass-transition temperature of 0.degree. C. through 46.degree. C.
and a softening point of 75.degree. C. through 110.degree. C.
The toner used in the present invention contains the resin having a
glass-transition temperature of 0.degree. C. through 46.degree. C.,
preferably 30.degree. C. through 50.degree. C., and a softening
point of 75.degree. C. through 110.degree. C., preferably
80.degree. C. through 99.degree. C. Inclusion of the resin having a
glass-transition temperature and softening point within the
aforementioned range allows a toner image to be melted and fixed on
a transfer sheet at the temperature much lower than the
conventional temperature.
The toner that permits image formation at a fixing temperature
lower than the conventional level is typically represented by the
toner having a core shell structure. The toner particles having a
core shell structure has a structure wherein a shell layer is
arranged on the core particles surface. The following describes the
toner particles having a core shell structure.
The core particles constituting the core shell structure contain at
least a binding resin and coloring agent. Further, a plurality of
types of binding resins having different glass-transition
temperatures and softening points can be contained for the purpose
of ensuring compatibility between low-temperature fixing
performance and mechanical strength. For example, when the toner
used in the present invention is designed as a core shell structure
toner, the toner characterized by compatibility between
low-temperature fixing performance and mechanical strength is
expected to be manufactured, if the resin having a glass-transition
temperature of 0.degree. C. through 46.degree. C. and a softening
point of 75.degree. C. through 110.degree. C. is contained as a
core.
The toner having a core shell structure is manufactured by the
following procedure, for example: Resin particles are formed by the
polymerization method called the suspension polymerization,
emulsion polymerization or multiple-layer polymerization. The resin
particles having been formed are coagulated and fused together with
the coloring agent particles (or coloring resin particles) in the
presence of a coagulant, whereby the core particles are
manufactured. Separately prepared resin particle dispersion is
added to the core particles (coagula between resin particles and
coloring agent particles) having been formed so that at least one
shell layer is created on the core. In this way, toner particles
including a core shell structure are produced by the process of
forming a shell layer on the core surface.
Addition of an external additive to the toner particles having been
generated produces the toner having a core shell structure. The
specific method for manufacturing the toner having a core shell
structure will be described later.
In the toner having a core shell structure, the glass-transition
point of the resin constituting the core is normally lower than
that of the resin constituting the shell.
The following describes how to measure the glass-transition
temperature, softening point and volume-based median diameter of
toner.
The glass-transition temperature of the toner constituting resin is
measured by a DSC (differential scanning calorimeter). The point of
a change in the inclination of the base line is expressed by the
temperature corresponding to the crossing point of the tangential
of the base line. To put it more specifically, the temperature
rises to 100.degree. C., and the sample is left standing for three
minutes at that temperature. After that, the sample is cooled down
to the room temperature at a falling temperature of 10.degree. C.
per minute. Then when this sample is measured at a rising
temperature of 1020 C. per minute, the crossing point between the
extension of the base line equal to or below the glass-transition
point and the tangential exhibiting the maximum inclination
subsequent to increase in the inclination relative to the base line
temperature is expressed in terms of glass-transition temperature.
The measuring instrument used in this case is exemplified by DSC-7
by Perkin-Elmer Inc.
The softening point of the resin constituting the toner can be
measured by a flow tester. To put it more specifically, a flow
tester "CFT-500" (by Shimadzu Seisakusho Ltd.) is used, and a
sample of 1 cm.sup.3 is melted and flown at a die pore diameter of
1 mm, a length of 1 mm, a load of 20 kg/cm.sup.2, a temperature
rising speed of 6.degree. C. per minute, and a temperature rising
start temperature of 50.degree. C. In this case, the temperature
corresponding to the point of flowing out 5 mm from the outflow
starting point is defined as a softening point.
The toner that can be used in this invention has a volume-based
median diameter (D50) of 3.5 .mu.m through 8.5 .mu.m, preferably
4.0 .mu.m through 7.0 .mu.m. If the volume-based median diameter is
kept within the aforementioned range, a minute dot image on the
level of 1200 dpi (dpi: number of dots per inch (2.54 cm) and a
high-definition full-color pictorial image, for example, can be
formed with high precision.
The volume-based median diameter of the toner can be measured and
calculated by connecting Multisizer 3 (by Beckmann Coulter Inc.)
with a computer loaded with a data processing program.
The following measuring procedure is used: After 0.02 g of toner
has been sufficiently blended with 20 ml of surface active agent
solution (e.g., a surface active agent solution obtained by
diluting a neutral detergent containing a surface active agent
component with demineralized water to a ratio of one to ten, for
the purpose of dispersing toner), dispersion by ultrasonic wave is
performed for one minute to produce toner dispersion. This toner
dispersion is poured into the beaker containing ISOTONII (by
Beckmann Coulter Inc.) inside the sample stand by a pipette until
the measured density falls within the range of 5% through 10%, and
the count of the measuring instrument is set at 2,500, whereby
measurement is started. The Multisizer 3 having an aperture
diameter of 50.mu.m was used in this test.
The following describes the elements constituting the toner that
can be used in the present invention.
The resin that can be used for each of the core and shell of the
toner that can be used in the present invention is exemplified by a
polymer obtained by polymerization of the following polymerizable
monomer:
The polymerizable monomer is exemplified by: styrene or styrene
derivative such as styrene, o-methylstyrene, m-methylstyrene,
p-methylstyrene, .alpha.-methylstyrene, p-phenylstyrene,
p-ethylstyrene, 2,4-dimethylstyrene, p-tert-butylstyrene,
p-n-hexylstyrene, p-n-octylstyrene, p-n-nonylstyrene,
p-n-desylstyrene and p-n-dodecyl styrene; methacrylate ester
derivative such as methacrylate methyl, methacrylate ethyl,
methacrylate n-butyl, methacrylate isopropyl, methacrylate
isobutyl, methacrylate t-butyl, methacrylate n-octyl, methacrylate
2-ethylhexyl, methacrylate stearyl, methacrylate lauryl,
methacrylate phenyl, methacrylate diethyl amino ethyl and
methacrylate dimethyl amino ethyl;
acrylic acid ester derivatives such as methyl acrylate, ethyl
acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate,
isobutyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, stearyl
acrylate, lauryl acrylate, and phenyl acrylate;
olefins such as ethylene, propylene and isobutylene;
vinyl esters such as vinyl propionate, vinyl acetate and vinyl
benzoate;
vinyl ethers such as vinyl methyl ether and vinyl ethyl ether;
vinyl ketones such as vinyl methyl ketone, vinyl ethyl ketone and
vinyl hexyl ketone;
N-vinyl compound such as N-vinyl carbazole, N-vinyl indole and
N-vinyl pyrrolidone;
vinyl compounds such as vinyl naphthalene and vinyl pyridine;
acrylic acid such as acrylonitrile, methacrylo nitrile and
acrylamide; and
methacrylate derivative.
These vinyl based monomers can be used independently or in
combination.
The substances containing ionic dissociation group can also be
combined for use, as exemplified by those containing a substituent
such as a carboxyl group, sulfonic acid group and phosphoric acid
group as a constituent group of the monomer. To put it more
specifically, they are acrylic acid, methacrylate, maleic acid,
itaconic acid, cinnamic acid, fumaric acid, maleic acid monoalkyl
ester, itaconic acid monoalkyl ester, styrene sulfonic acid group,
alyl sulfosuccinic acid, 2-acrylamide-2-methylpropane sulfonic acid
and acid phosphoxy ethylmethacrylate.
Further, a resin of crosslinking structure can be produced by using
the multifunctional vinyl such as divinyl benzene, ethylene glycol
dimethacrylate, ethylene glycol diacylate, diethylene glycol
dimethacrylate, diethylene glycol diacylate, triethylene glycol
dimethacrylate, triethylene glycol diacylate, and neopentyl glycol
dimethacrylate and neopentyl glycol diacylate.
The following describes the waxes that can be used for toner. These
waxes include those that have been known so far in the conventional
art. They are: a polyolefin wax such as polyethylene wax and
polypropylene wax;
a long chain hydrocarbon based wax such as paraffin wax and sasol
wax;
a dialkyl ketone based wax such as distearyl ketone;
an ester based wax such as carnauba wax, montan wax, trimethylol
propane tribehenate, pentaerithritol tetramyristate,
pentaerithritol tetrastearate, pentaerithritol tetrabehenate,
pentaerithritol diacetate dibehenate, glycerinetribehenate,
1,18-octadecane diol distearate, tristealyl trimellitate, and
distearyl maleate; and
an amide based wax such as ethylene diamine dibehenylamide and
tristealylamide trimellitate.
The melting point of the wax is normally 40.degree. C. through
160.degree. C., preferably 50.degree. C. through 120.degree. C.,
more preferably 60.degree. C. through 90.degree. C. When the
melting point is kept within the aforementioned range, the
heat-resistant storage stability of toner is ensured, and such a
trouble as cold offset does not occur even when low-temperature
fixing is performed. Stable toner image forming is provided.
Further, the amount of wax contained in the wax is preferably 1
percent by mass through 30 percent by mass, more preferably 5
percent by mass through 20 percent by mass.
The coloring agent that can be used is exemplified by the
following:
The black coloring agent is exemplified by a carbon black such as a
furnace black, channel black, acetylene black, thermal black and
lamp black, as well as a magnetic substance such as a magnetite and
ferrite.
Further, the coloring agents of magenta or red include C.I. pigment
red 2, C.I. pigment red 3, C.I. pigment red 5, C.I. pigment red 6,
C.I. pigment red 7, C.I. pigment red 15, C.I. pigment red 16, C.I.
pigment red 48;1, C.I. pigment red 53;1, C.I. pigment red 57;1,
C.I. pigment red 122, C.I. pigment red 123, C.I. pigment red 139,
C.I. pigment red 144, C.I. pigment red 149, C.I. pigment red 166,
C.I. pigment red 177, C.I. pigment red 178 and C.I. pigment red
222.
The coloring agents for orange or yellow include C.I. pigment
orange 31, C.I. pigment orange 43, C.I pigment yellow 12, C.I.
pigment yellow 13, C.I. pigment yellow 14, C.I. pigment yellow 15,
C.I. pigment yellow 17, C.I. pigment yellow 93, C.I. pigment yellow
94 and C.I. pigment yellow 138.
The coloring agents for green or cyan include C.I. pigment blue 15,
C.I. pigment blue 15;2, C.I. pigment blue 15;3, C.I. pigment blue
15;4, C.I. pigment blue 16, C.I. pigment blue 60, C.I. pigment blue
62, C.I. pigment blue 66 and C.I. pigment green 7.
These coloring agents can be used independently or in combination,
as required. Further, the amount of coloring agent to be added is
set at 1 through 30 percent by mass, with respect to the total
amount of toner, preferably 2 through 20 percent by mass.
The following describes the typical method of manufacturing the
toner that can be used in the present invention:
The following methods, for example, can be used to manufacture the
toner having a core shell structure that can be used in the present
invention--(1) a melting/dispersion process for melting or
dispersion in the radical polymerizable monomer; (2) a
polymerization process for preparing the dispersion of resin
particles; (3) a coagulation/fusion process for obtaining core
particles (associated particles) by coagulation, fusion of resin
particles and coloring agent particles in the aqueous medium; (4) a
first curing process for curing associated particles by thermal
energy and regulating the shape; (5) a shell forming process
wherein resin particles for shell are added into the dispersion of
core particles (associated particles) to cause coagulation and
fusion of the shell particles, whereby the colored particles of
core shell structure are formed on the core particles surface; (6)
a second curing process for curing the colored particles of core
shell structure by thermal energy and regulating the shape of the
colored particles of core shell structure are cured; (7) a cleaning
process for separating between the solid and liquid of colored
particles from the colored particle dispersion having been cooled,
and removing the surface active agent and others from these colored
particles; (8) a drying process for drying the colored particles
having been cleaned; and (9) a process of adding external additives
to dried colored particles, subsequent to the drying process, if
required. The aforementioned processes will be described later.
When the toner having a core shell structure is manufactured,
colored particles as a core (hereinafter referred to as "core
particles") are manufactured by association and fusion between
resin particles and coloring agent particles. Then resin particles
are added into the core particle dispersion to cause coagulation
and fusion of these resin particles to the core particles surface,
whereby the core particles surface is covered, and colored
particles having a core shell structure are manufactured. As
described above, the toner having a core shell structure is
manufactured by adding resin particles into the dispersion of core
particles manufactured by various production methods, and fusing
the resin particles on the core particles surface.
The core particles constituting the toner of core shell structure
are manufactured by coagulation and fusion between the resin
particles and coloring agent particles. The shape of core particles
is controlled by controlling the heating temperature in the
coagulation/fusion process and heating temperature and time in the
first curing process. To be more specific, when a lower heating
temperature is used in the coagulation/fusion process, the progress
of fusion between resin particles is checked, and deformation is
promoted. Further, the deformed shape of the core particles can be
controlled by setting a lower heating temperature and shorter time
in the first curing process.
Of these methods, time control in the first curing process is most
effective. The curing process is intended to regulate the
circularity of the associated particles. If this time is prolonged,
associated particles will be shaped closer to perfect
sphericity.
The following describes the details of the method of manufacturing
the toner of the aforementioned core shell structure:
To manufacture the core section constituting the toner of the
present invention, the wax component is dissolved and dispersed in
the polymerizable monomer forming the resin, for example. Then
mechanical particles are dispersed in the aqueous medium, and the
polymerizable monomer is polymerized according to the mini-emulsion
polymerization method. The composite resin particles and coloring
agent particles formed through this process are salted out and
fused, whereby particles are associated. This method is preferably
employed. The mold releasing agent component can be dissolved or
melted in the polymerizable monomer.
The core section is preferably manufacturing according to the
process of salting out and fusion of the composite resin particles
and coloring agent particles including the resin obtained by the
multi-polymerization method. To put it more specifically, the
following methods can be mentioned:
[Melting/Dispersion Process]
In this process, the mold releasing agent compound is dissolved in
the radical polymerizable monomer, and the radical polymerizable
monomer solution mixed with the mold releasing agent compound is
prepared.
[Polymerization Process]
In a preferred example of this polymerization process, the radical
polymerizable monomer solution containing the melted or dispersed
mixture of the aforementioned ester compound is added in the
aqueous medium including the surface active agent without exceeding
critical micelle density (CMC). Then mechanical energy is applied
thereto to form a liquid particle. After that, a water-insoluble
radical polymerization initiator is added to promote the
polymerization reaction in this liquid particle. An oil soluble
polymerization initiator may be included in the aforementioned
liquid particles. In such a polymerization process, it is essential
to provide mechanical energy and to apply a process of forcible
emulsification (formation of liquid particles). A device for
providing such mechanical energy is exemplified by the device for
providing strong agitation or ultrasonic wave vibration energy such
as a homo-mixer, ultrasonic wave and Manton-Gaulin.
The aforementioned polymerization process provides the resin
particles including the mixture of ester compound and binding
resin. Such resin particles can be colored particles or uncolored
particles. The colored resin particles can be obtained by
polymerization of the monomer composition containing the coloring
agent. When uncolored resin particles are used, the dispersion of
coloring agent particles is added to the dispersion of resin
particles in the coagulation/fusion process (to be described
later). Thus, colored particles can be obtained by fusion of the
resin particles and coloring agent particles.
[Coagulation/Fusion Process] (Including the First Curing
Process)
The salting out/fusion method using the resin particles (colored or
non-colored resin particles) obtained by the polymerization process
is preferably employed as a method for coagulation and fusion in
the aforementioned fusion process. Further, together with the resin
particles and coloring agent particles, internal additive particles
such as mold releasing agent particles and electric charge
inhibitor can be coagulated and fused in the coagulation/fusion
process.
The salting out/fusion method in the sense in which it is used here
refers to a method of association wherein coagulation and fusion
are performed in parallel at the time of associating the particles,
and, when particles have grown up to a desired particle diameter, a
coagulation terminator is added to terminate the growth of the
particles. In this case, heating is continued, if required, to
control the shape of the particles.
The "aqueous medium" in the aforementioned coagulation/fusion
process refers to the medium wherein water is the main component
(50 percent by mass or more). In this case, an organic solvent that
dissolves in water can be mentioned as one of the components other
than water. It is exemplified by methanol, ethanol, isopropanol,
butanol, acetone, methylethyl ketone and tetrahydrofuran.
The coloring agent particles can be prepared by dispersing the
coloring agent in the aqueous medium. The coloring agent is
dispersed when the surface active agent density equal to or greater
than the critical micelle density (CMC) under water. There is no
restriction to the type of the equipment used to disperse the
coloring agent. The equipment that can be preferably used includes
an ultrasonic wave homogenizer, mechanical homogenizer, pressure
type homogenizer such as a Manton-Gaulin and pressure type
homogenizer, sand grinder, Getzmann mill, diamond fine mill and a
medium type homogenizer. The aforementioned surface active agents
can be mentioned as the surface active agent to be used. The
coloring agent (particles) may have been subjected to surface
modification. Surface modification of the coloring agent was
performed by dispersing a coloring agent in solvent and adding a
surface modifying agent to that molecular weight solution. The
temperature was raised to cause reaction of this system. Upon
completion of reaction, the coloring agent was filtered, and
cleaning and filtration were repeated using the same solvent. After
that, it was dried to get a coloring agent (pigment) processed by
surface modifying agent.
In the salting out/fusion method, which is a preferred method for
coagulation and fusion, an alkaline metal salt, alkaline earth
metal salt and salting agent made up of a trivalent salt and others
are added in water containing resin particles and coloring agent
particles as a coagulant having a density equal to or greater than
the critical coagulation density. Then the solution was heated at
the glass-transition temperature equal to or greater than that of
the aforementioned resin particles, to reach the temperature equal
to or greater than the melting peak temperature (.degree. C.) of
the aforementioned mixture, whereby salting is promoted. At the
same time, fusion is carried out in this process. An alkaline metal
salt and alkaline earth metal salt are as a salting agent. Lithium,
potassium and sodium can be mentioned as an alkaline metal.
Magnesium, calcium, strontium and barium can be mentioned as an
alkaline earth metal. Potassium, sodium, magnesium, calcium and
barium are preferably used.
When the salting out/fusion method is used to cause coagulation and
fusion, it is preferred to minimize the time for leaving the
solution to stand subsequent to addition of the salting agent. The
reason for this is not very clear. A fluctuation in the state of
coagulation of the particles is caused by the time for leaving the
solution to stand subsequent to salting out. This will result in
unstable distribution of the particle diameter and will raise a
problem of fluctuation in the surface property of the surface of
the used toner. Further, the temperature for adding the salting
agent should be equal to or less than the glass-transition
temperature of resin particles. This can be explained as follows:
If the temperature for adding the salting agent is greater than the
glass-transition temperature of resin particles, the particle
diameter cannot be controlled, even if the salting out/fusion of
resin particles proceeds at a higher speed. This will cause such a
problem as production of the particles of larger particle diameter.
The temperature for adding the salting agent should be equal to or
less than the glass-transition temperature of the resin. This
temperature is generally 5.degree. C. through 55.degree. C.,
preferably 10.degree. C. through 45.degree. C.
The salting agent is added at the temperature equal to or less than
the glass-transition temperature of the resin particles. After
that, the temperature is increased as quickly as possible. The
solution is heated at the glass-transition temperature equal to or
greater than that of the resin particles, to reach the temperature
equal to or greater than the melting peak temperature (.degree. C.)
of the aforementioned mixture. The time duration for this
temperature rise is preferably less than one hour. This requires
quick temperature rising operation. The temperature rising speed is
preferably equal to or greater than 0.25.degree. C. per minute. The
upper limit is not yet clear, but the abrupt rise of temperature
will cause the salting out operation to proceed quickly. This makes
it difficult to control the particle diameter. Thus, the preferred
speed is equal to or less than 5.degree. C. per minute. This fusion
process provides the dispersion of associated particles (core
particles) created by salting out/fusion of resin particles and
desired particles.
The heating temperature in the coagulation/fusion process and the
heating temperature and time in the first curing process are
controlled in such a way that the formed core particles will have a
roughened structure. To put it more specifically, a lower heating
temperature is used in the coagulation/fusion process and the
progress in the fusion among resin particles is controlled to
promote deformation. Alternatively, a lower heating temperature and
shorter time are used in the first curing process, wherein core
particles are controlled to be roughened.
[Shell Making Process] (Including the Second Curing Process)
In the shell making process, a resin particles dispersion for shell
is added into the core particles dispersion, and resin particles
for shell are coagulated and fused on the core particles surface so
that core particles surface is coated with resin particles for
shell, whereby colored particles are formed.
To put it more specifically, while the temperature in the
aforementioned coagulation/fusion process and the first curing
process is kept unchanged, the dispersion of the resin particles
for shell is added. While heating and agitation operations are
continued, the core particles surface is coated with the resin
particles for shell slowly for several hours, whereby colored
particles are formed. The time for heating and agitation is
preferably 1 through 7 hours, more preferably 3 through 5 hours.
When the diameter of the colored particles has reached a
predetermined level through formation of the shell, a terminator
such as a sodium chloride is added to suspend the growth of
particles. After that, to fuse the resin particles for shell
attached onto the core particles, heating and agitation continue
for several hours. In the shell making process, a shell having a
thickness of 10 nm through 500 nm is formed on the core particles
surface. In this manner, resin particles stick onto the core
particles surface to form a shell. Thus, round and regular-shaped
colored particles are produced.
Through the aforementioned process, round and regular-shaped
colored particles are produced. Further, colored particles can be
controlled to be shaped closer to perfect sphericity by setting a
longer time in the second curing process or a higher curing
temperature.
[Cooling Process]
This is the process of cooling (quenching) the dispersion of the
aforementioned colored particles. Cooling is provided at a cooling
speed of 1.degree. C. through 20.degree. C. per minute. There is no
restriction to the method of cooling. Cooling can be provided by
leading coolant from outside the reaction container, or by
introducing coolant directly into the reaction system.
[Solid/Liquid Separation/Cleaning Process]
The solid/liquid separation/cleaning process contains a
solid/liquid separation step for solid/liquid separation of the
colored particles from the dispersion of colored particles cooled
down to a predetermined temperature in the aforementioned process,
and a cleaning step for removing such an deposit as a surface
active agent or salting agent from the toner cake (wet colored
particles coagulated in a form of a cake) having been subjected to
the step of solid/liquid separation. In this case, there is no
restriction to the method of filtration. A centrifugal separation
method, vacuum filtration method based on Nutze and others or
filter press can be used.
[Drying Process]
This is the process wherein the cleaned toner cake is dried to get
dried colored particles. A spray dryer, vacuum frozen drying
machine and vacuum drying machine can be mentioned as the drying
machine that can be used in this process. Use of a standing rack
drying machine, movable rack drying machine, fluid bed drying
machine, rotary type drying machine and agitation type drying
machine is preferred. The water content of the dried colored
particles is preferably, equal to or less than 5 percent by mass,
more preferably equal to or less than 2 percent by mass. When dried
colored particles are coagulated by a weak attraction among
particles, the coagula can be crushed. In this case, a mechanical
type crushing apparatus such as a jet mill, Henschel mixer, coffee
mill and food processor can be used as a crusher.
[External Addition Process]
In this process, dried colored particles are blended with an
external additive, as required, whereby toner is manufactured.
The mechanical type blending machine such as a Henschel mixer and
coffee mill can be used as an external additive blending
apparatus.
The following describes the polymerization initiator,
chain-transfer agent and surface active agent that can be used in
the aforementioned toner manufacturing method.
The resin constituting the core and shell of the toner in the
present invention is generated by polymerization of the
aforementioned polymerizable monomer. Polymerization of the
polymerizable monomer is started in the presence of a radical
polymerization initiator. The following can be mentioned as the
radical polymerization initiator. To put it more specifically, when
resin particles are to be formed according to the method of
suspension polymerization, the oil soluble polymerization initiator
can be used. The oil soluble polymerization initiator that can be
used is exemplified by an azo based substance such as
2,2'-azobis-(2,4-dimethylvaleronitrile), 2,2'-azobis isobutylo
nitrile, 1,1'-azobis(cyclohexanone-1-carbonitrile),
2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile and azobisisobutyro
nitrile; a peroxide based polymerization initiator such as a diazo
polymerization initiator, benzoyl peroxide, methylethyl ketone
peroxide, diisopropyl peroxy carbonate, cumene hydroperoxide,
t-butyl hydro peroxide, di-t-butyl peroxide, dicumyl peroxide,
2,4-dichlorobenzoyl peroxide, lauroyl peroxide,
2,2-bis-(4,4-t-butyl peroxy cyclohexyl)propane, and tris-(t-butyl
peroxy)triazine; and a macromolecule initiator having a peroxide on
the side chain.
When resin particles are to be formed according to the method of
emulsion polymerization, the water soluble radical polymerization
initiator can be utilized. The water soluble polymerization
initiator is exemplified by persulfide such as potassium peroxide
and ammonium peroxide, as well as azobis amino dipropane acetate,
azobiscyano valeric acid and valerate and hydrogen peroxide.
A dispersion stabilizer can be used to ensure that an adequate
amount of polymerizable monomer or the like is dispersed in the
reaction system. The dispersion stabilizer that can be used is
exemplified by the following substances generally employed as
surface active agents: tricalcium phosphate, magnesium phosphate,
zinc phosphate, aluminum phosphate, calcium carbonate, magnesium
carbonate, hydroxide calcium, hydroxide magnesium, hydroxide
aluminum, calcium methasilicate, calcium sulfate, barium sulfate,
bentonite, silica, and alumina. Further, polyvinyl alcohol,
gelatine, methyl cellulose, sodium dodecyl benzene sulfonate,
adduct of ethylene oxide, and higher alcohol sodium sulfate.
The chain-transfer agent that can be used includes the
chain-transfer agents that are commonly employed to adjust the
molecular weight of the resin constituting the composite resin
particles.
There is no restriction to the type of the chain-transfer agent. It
is exemplified by mercaptan such as octylmercaptan, dodecyl
mercaptan and tert-dodecyl mercaptan, as well as n-octyl-3-mercapto
propionic acid ester, terpinolene, carbon tetrabromide and
.alpha.-methylstyrene dimer.
The following describes the surface active agent used to prepare
the toner that can be used in the present invention:
To perform polymerization using the aforementioned radical
polymerizable monomer, a surface active agent must be used to
perform oil drop dispersion in the aqueous medium. There is no
restriction to the type of the surface active agent that can be
used in this case, the following ionic surface active agents can be
preferably used.
The ionic surface active agent is exemplified by sulfonate (sodium
dodecyl benzene sulfonate, sodium arylalkyl polyether sulfonate,
3,3-disulfone diphenyl urea-4,4-diazo-bis-amino-8-naphthol-6-sodium
sulfonate, ortho-carboxy benzene-azo-dimethyl aniline,
2,2,5,5-tetramethyl-triphenylmethane-4,4-diazo-bis-.beta.-naphthol-6-sodi-
um sulfonate, etc.), ester sulfate salt (sodium dodecyl sulfate,
sodium tetradesyl sulfate, sodium pentadesyl sulfate, sodium octyl
sulfate, etc.), fatty acid salt (sodium oleate, sodium laurate,
sodium caprate, sodium caprylate, sodium caproate, and potassium
stearate, calcium oleate).
A nonionic surface active agent can also be used. It is exemplified
by polyethylene oxide, polypropylene oxide, a combination between
polypropylene oxide and polyethylene oxide, ester between
polyethylene glycol and higher fatty acid, alkylphenol polyethylene
oxide, ester between higher fatty acid and polyethylene glycol,
ester between higher fatty acid and polypropylene oxide, and
sorbitan ester.
EXAMPLE
The following describes the embodiment of the present invention
with reference to examples, without the present invention being
restricted thereto.
1. Preparation of Toner
(Preparation of Wax Dispersion (1))
680 parts of distilled water, 180 parts of carnauba wax (by
Cerarica Noda KK), and 17 parts of sodium dodecyl benzene sulfonate
("Neogen SC" (by Daiichi Kogyo Seiyaku Co., Ltd.) were mixed, and
high pressure shearing force was applied to emulsify and disperse
the mixture to get a wax particles dispersion. The average diameter
of the wax particles was measured by a dynamic light-scattering
particle size distribution measuring instrument "ELS-800" (by
Otsuka Denshi Kogyo KK). The result was 110 nm.
(Preparation of Wax Dispersion (2))
680 parts of distilled water, 180 parts of pentaerithritol ester
("Unistar H476" (by NOF Corp.), and 17 parts of sodium dodecyl
benzene sulfonate ("Neogen SC" (by Daiichi Kogyo Seiyaku Co., Ltd.)
were mixed, and high pressure shearing force was applied to
emulsify and disperse the mixture to get a wax particles
dispersion. The average diameter of the wax particles was measured
by a dynamic light-scattering particle size distribution measuring
instrument "ELS-800" (by Otsuka Denshi Kogyo KK). The result was
130 nm.
(Preparation of Coloring Agent Particles Dispersion (1))
10 parts of dodecyl benzene sodium sulfonate ("Neogen SC" ((by
Daiichi Kogyo Seiyaku Co., Ltd.)) were dissolved in 180 parts of
distilled water. 25 parts of carbon black ("Regal 330CR" (by
Cabot)) were added to this mixture as coloring agent particles, and
were dispersed to prepare the coloring agent particles dispersion
(1). The average particle diameter of carbon black in the coloring
agent particles dispersion (1) was measured by a dynamic
light-scattering particle size distribution measuring instrument
"ELS-800" (by Otsuka Denshi Kogyo KK). The result of measurement
was 106 nm.
(Preparation of Polymer Primary Particles Dispersion (1))
450 parts of distilled water and 0.56 parts of dodecyl sodium
sulfate were added to the reactor equipped with an agitating
apparatus, cooling tube and temperature sensor. While this mixture
was agitated under the flow of nitrogen gas, the temperature was
raised to 80.degree. C. 120 parts of 1 percent by mass of an
aqueous solution containing potassium persulfate were added
thereto. Then the monomer mixture (1) of the following composition
was added for 1.5 hours. After that, it was kept for further two
hours, and polymerization was terminated. After termination of
polymerization reaction, the mixture was cooled down to the room
temperature to obtain the milk white polymer primary particles
dispersion (1). The weight average molecular weight of polymer was
11,000. The glass-transition temperature was 34.degree. C. and the
softening point was 82.degree. C. The average particle diameter was
measured by the dynamic light-scattering particle size distribution
measuring instrument "ELS-800" (by Otsuka Denshi Kogyo KK). The
result was 120 nm.
<Monomer Mixture (1)>
TABLE-US-00001 Styrene 99 parts Butyl acrylate 52 parts
Methacrylate 14 parts n-octylmercaptan 6 parts
(Preparation of Polymer Primary Particles Dispersion (2))
45 parts of wax dispersion (2), 450 parts of distilled water and
0.56 parts of dodecyl sodium sulfate were added to the reactor
equipped with an agitating apparatus, cooling tube and temperature
sensor. While this mixture was agitated under the flow of nitrogen
gas, the temperature was raised to 80.degree. C. 120 parts of 1
percent by mass of an aqueous solution containing potassium
persulfate were added thereto. Then the monomer mixture (2) of the
following composition was added for 1.5 hours. After that, it was
kept for further two hours, and polymerization was terminated.
After termination of polymerization reaction, the mixture was
cooled down to the room temperature to obtain the milk white
polymer primary particles dispersion (2). The weight average
molecular weight of polymer was 48,000. The glass-transition
temperature was 55.degree. C. and the softening point was
110.degree. C. The average particle diameter was measured by the
dynamic light-scattering particle size distribution measuring
instrument "ELS-800" (by Otsuka Denshi Kogyo KK). The result was
130 nm.
<Monomer Mixture (2)>
TABLE-US-00002 Styrene 120 parts Butyl acrylate 38 parts
Methacrylate 13 parts n-octylmercaptan 3 parts
(Preparation of Polymer Primary Particles Dispersion (3))
450 parts of distilled water and 0.56 parts of dodecyl sodium
sulfate were added to the reactor equipped with an agitating
apparatus, cooling tube and temperature sensor. While this mixture
was agitated under the flow of nitrogen gas, the temperature was
raised to 80.degree. C. 120 parts of 1 percent by mass of an
aqueous solution containing potassium persulfate were added
thereto. Then the monomer mixture (3) of the following composition
was added for 1.5 hours. After that, it was kept for further two
hours, and polymerization was terminated. After termination of
polymerization reaction, the mixture was cooled down to the room
temperature to obtain the milk white polymer primary particles
dispersion (3). The weight average molecular weight of polymer was
9,800. The glass-transition temperature was 30.degree. C. and the
softening point was 78.degree. C. The average particle diameter was
measured by the dynamic light-scattering particle size distribution
measuring instrument "ELS-800" (by Otsuka Denshi Kogyo KK). The
result was 110 nm.
<Monomer mixture (3)>
TABLE-US-00003 Styrene 95 parts Butyl acrylate 58 parts
Methacrylate 12 parts n-octylmercaptan 8 parts
(Preparation of Toner 1)
240 parts of polymer primary particles dispersion (1), 13.6 parts
of wax dispersive wave (1), 24 parts of coloring agent particles
dispersion (1), 5 parts of anionic surface active agent ("Neogen
SC" (by Daiichi Kogyo Seiyaku Co., Ltd.) and 240 parts of distilled
water were added to the reactor equipped with an agitating
apparatus, cooling tube and temperature sensor. While the mixture
was agitated, 2 mol/liter of aqueous solution containing hydroxide
sodium was added, and the pH value of the mixed dispersion was
adjusted to 10.0. 40 parts of 50 percent by mass of aqueous
solution containing magnesium chloride were added to this mixture.
After that, while the mixture was agitated, the temperature was
raised to 80.degree. C. After that, it was kept for further 0.5
hours. Then the temperature was raised to 88.degree. C. After that,
it was kept for further 0.5 hours. The toner in the mixed
dispersion at this time had an average particle diameter of 4.2
.mu.m.
The temperature in the system was cooled down to 75.degree. C.
After that, 20 parts of polymer primary particles dispersion (2)
were added and the temperature was raised to 83.degree. C. It was
kept for 1.5 hours. After that, 30 parts of polymer primary
particles dispersion (2) were added and the temperature was raised
to 85.degree. C. After it was kept for 1.5 hours, 120 g of 20
percent by mass of aqueous solution containing sodium chloride were
added. The temperature was then raised to 92.degree. C. and was
kept for further 1 hour. After that, the mixture was cooled down to
the room temperature. A process of cleaning operations such as
filtration of the solution and re-suspension of the obtained solid
in the distilled water were repeated several times. The mixture was
then dried to get toner particles 1 having a volume-based median
diameter of 4.6 .mu.m. The glass-transition temperature of the
obtained toner particles 1 was 36.degree. C., and the softening
point was 84.degree. C.
0.5 parts of hydrophobic silica ("H-2000" (by Clariant), 1.0 parts
of titanium oxide ("STT30A" (Titan Kogyo K.K.)) and 1.0 parts of
strontium titanate (average particle diameter 0.2 .mu.m) were added
to 100 parts of this toner particles. The mixture was mixed by a
Henschel mixer (at a peripheral speed of 40 m/sec., 60 sec.) and
was processed by a screen having an aperture of 90 .mu.m, whereby
toner 1 was obtained.
1. Preparation of Toner 2
Toner 2 was prepared by the same procedure except that the polymer
primary particles dispersion (2) instead of the polymer primary
particles dispersion (1) was used to prepare the toner 1. The
volume-based median diameter of the toner 2 was 4.8 .mu.m. The
glass-transition temperature was 32.degree. C. and the softening
point was 79.degree. C.
2. Preparation of Toner Cartridge
Eight types of toner cartridges made up of an packaging container
having the specifications shown in Table 1, and a storage container
of low-density polyethylene containing toner 1 or 2 were prepared.
They are shown as Examples 1 through 7, and Comparative Examples 1
through 3.
3. Evaluation Test
The toner cartridge having been manufactured was mounted on the
commercially available image forming apparatus BIZHUB PRO 1050.TM.
(by Konica Minolta Co., Ltd.). One thousand sheets were printed per
day at 30.degree. C. with a relative humidity of 55% RH for the
following evaluation. Printing was provided using a text image with
a pixel rate of 7%, a thin line image made up of a plurality of
fine lines arranged at an interval of 1.5 mm, and an original image
(A4) with each of solid white image and sold black image accounting
for a quarter equal part.
<Toner Coagulation>
Image formation by coagulation toner was evaluated by observing the
thin line portion of the resolution image in the first and last
prints having been outputted at the time of printing 1000 sheets,
using a magnifier.
A: Immediately after installation on the image forming apparatus, a
roughened structure on the thin line edge was not confirmed until
toner in the cartridge was used up.
B: When toner was about to be used up, a slight roughened structure
on the thin line edge was observed, but no overlap of thin lines
was confirmed.
C: In the intermediate phase during the test, a slight roughened
structure was observed on the thin line edge, but no overlap of
thin lines was confirmed.
D: Overlap of thin lines occurred due to the roughened structure of
the thin line edge, and the presence of a plurality of thin lines
cannot be confirmed.
<Toner Spill>
A spill of toner at the time of installation on the image forming
apparatus was found out by visual observation.
B: Toner spill was not observed.
D: Toner spill was confirmed. A spotted image defect occurred.
<Missing Transfer>
A test was conducted to evaluate solid black images in the first
and last prints having been outputted at the time of printing 1000
sheets, and white spots resulting from missing transfer through
observation by a magnifier.
A: Immediately after installation on the image forming apparatus,
no white spot was observed in the solid black image or text image
until toner in the cartridge was used up.
B: When toner was about to be used up, a slight white spot was
observed on the solid black image, but there was no problem
according to the visual observation.
C: A white spots was observed on the solid black image in the
intermediate phase of test, but there was no problem according to
the visual observation.
D: A white spot was confirmed on the solid black image. A white
spot was also observed on the text image.
Table 1 shows the results of the test.
TABLE-US-00004 TABLE 1 Packaging container specifications
Evaluation test Struc- Toner Toner Missing Material ture *1 No. *2
spill transfer Example 1 Expandable FIG. 1 0.10 1 B B B
polyethylene Example 2 Paper-made FIG. 1 0.20 2 B B B corrugated
fiberboard Example 3 Paper-made FIG. 10 0.30 1 B B B corrugated
fiberboard (double) Example 4 Polyethylene- FIG. 1 0.15 1 A B A
made fiberboard Example 5 Polyethylene- FIG. 10 0.15 1 A B A made
fiberboard Example 6 Expandable FIG. 10 0.08 2 C B C polystyrene
Example 7 Polypropylene- FIG. 1 0.30 1 A B A made fiberboard Com
Polystyrene- FIG. 1 0.33 1 D B C parative- made Example 1
fiberboard Com- Air cap Bag 0.04 1 D D D parative body Example 2
Com- ABS FIG. 1 1.10 1 D D D parative Example 3 *1: Apparent
density, *2: Toner coagulation
As shown in Table 1, in Examples 1 through 7, satisfactory results
were obtained for tests on the toner coagulation, toner spill and
missing transfer. Especially, better results were obtained when the
resin-made packaging container was used than when the paper-made
packaging container was used. In the meantime, image errors caused
by toner coagulation were observed in all the Comparative Examples
1 through 3.
In the toner cartridge of the above embodiments, the storage
container accommodating the toner is packaged in a low-density
packaging container having hollow structure to ensure that the
stored toner is not affected by outside air. Thus, even if the
toner cartridge for storing the toner containing low-temperature
fixing property is not conveyed by a low-temperature trucking
vehicle, toner is not damaged by heat. Further, the cartridge
together with the packaging container can be mounted on the image
forming apparatus. Even when the toner of low-temperature fixing
property is used in the image forming apparatus installed in the
high-temperature environment, stable image formation can be
ensured, without the toner being affected by such installation
environment as dew condensation.
The cartridge of the aforesaid embodiments equipped with an
packaging container is mounted on an image forming apparatus. After
use, the cartridge together with the packaging container can be
collected for recycling. Thus, use of this toner cartridge does not
involve such a problem of generation of waste or loss of an
packaging container during the use with the image forming
apparatus. Thus, the present invention provides an
environment-friendly toner cartridge compatible with
low-temperature fixing, wherein the burden resulting from storage
of the packaging container is not imposed on a user.
In the aforesaid embodiments, the cartridge together with an
packaging container is mounted on an image forming apparatus. Thus,
the present invention provides a user-friendly toner cartridge of
enhanced usability which saves the user's time and effort of
packaging a contaminated container again in the packaging container
at the time of mounting the cartridge, or taking out the storage
container for accommodating the toner from the packaging
container.
* * * * *